A panoramic image is an image with a wide field of view. A panoramic image can have a field of view up to an entire sphere, that is 360 degrees in the horizontal dimension and 180 degrees in the vertical dimension.
Panoramic images can be computer generated using mathematical models, or they can be produced by seaming together a number of photographically captured images. The number of images which must be seamed to form a panorama is determined by the field of view of each of the images being seamed. For example a fisheye lens can capture a very wide filed of view, and as few as two such images can be seamed to form a spherical panorama.
Digital seaming technology is well developed. Computer programs are available which match the edges of images and which join a number of images to form a panorama. For example U.S. Pat. Nos. 5,023,925 and 5,703,604 describe a system for capturing images, seaming the images into panoramas, and for viewing selected portions of the panoramic images. Immersive Media Corp. (formerly Dodeca L.L.C.) located in Portland, Oreg., commercially markets a system for capturing images using a multi lens camera and for seaming images into panoramas. A image seaming program which runs on the Apple Macintosh computer system is marketed by Apple Computer Inc. under the name “The QuickTime VR Authoring Studio”
Computer programs which seam images into spherical panoramas align the images which are being seamed and then lay the end portion of one image over the end portion of an adjacent image. Generally the end portions of images that are overlapped are combined (i.e. averaged or feathered) in the area of a seam. In the overlap area, the contribution or optical dominance of each image goes from one hundred percent at the edge of the overlap region closest to the center of the image to zero percent contribution at the extreme edge of the image. The contribution can go from zero to one hundred percent on a straight line basis or according to some other selected curve.
In the area where the images overlap, visual artifacts will be created unless the images are precisely aligned. Aligning images into a panorama is particularly difficult because of warping. For example, when an image is moved in a vertical direction in order to match its vertical alignment to that of another image, the horizontal scale of the top of the image being moved is changed by a different amount than is the horizontal scale on the bottom of the image.
It is particularly difficult to align images in a multi row seamer, that is, in a seamer which joins multiple rows of images into a spherical panorama. Such seamers must align more than two edges of an image to different neighboring images.
There are a variety of other parameters which must also be selected when seaming images. Among the additional parameters is the focal length assigned to each of the images. The focal length of each image determines the image's field of view.
Thus, while it is possible to seam a number of images together to form a spherical panorama, it is very difficult to seam images into a panorama without creating visual artifacts (i.e. errors). Such visual artifacts detract from the overall visual effect. There are numerous sources of image positioning and image processing errors that create visual artifacts in seamed images. The sources of errors which produce visual artifacts in seamed images can include:                Inaccurate camera alignment between image capture,        unknown or varying focal length of the images        imprecise placement of lens nodal points when capturing images        vibration of a camera during image capture        mechanical tolerances in camera pan head mounting        film warping (i.e. the film is not flat during scanning)        optical errors or inconsistencies in the lens, film, camera or scanner        inaccurate or inconsistent image framing or registration during digitization        inaccuracy in warping an image when it is laid into a pan (i.e. the image is loaded at an incorrect angle,        focus changes made between capture of successive images        
With current technology, when an annoying visual artifact is detected in a seamed panorama, one or more of the images which is responsible for the artifact are edited with a program such as PhotoShop which is marketed by Adobe Corporation. The modified images are then seamed and the process is repeated if the artifact remains in the program. Alternatively, the entire seamed image can be touched up with an editor such as PhotoShop. Such operations are exceedingly tedious to perform.
Prior art seamer programs allow a user to adjust various parameters which determine how the images will be seamed, for example they allow a user to specify the image location or pitch above or below the horizon and the bank or tilt an image, that is, the angle to the horizon. However, with prior art computer program, such parameters are entered into the program, the seaming operation proceeds and then if the result is not satisfactory, the parameters must be changed and the process repeated in an iterative manner. If changes to one of the images is required, the image must be edited by using a image editor such a Adobe PhotoShop and the process is then repeated with the altered image.